Historically, the pneumatic tire has been fabricated as a laminate structure of generally toroidal shape having beads, a tread, belt reinforcement, and a carcass. The tire is made of rubber, fabric, and steel. The manufacturing technologies employed for the most part involved assembling the many tire components from flat strips or sheets of material. Each component is placed on a building drum and cut to length such that the ends of the component meet or overlap creating a splice.
In the first stage of assembly the prior art carcass will normally include one or more plies, and a pair of sidewalls, a pair of apexes, an innerliner (for a tubeless tire), a pair of chafers and perhaps a pair of gum shoulder strips. Annular bead cores can be added during this first stage of tire building and the plies can be turned around the bead cores to form the ply turnups. Additional components may be used or even replace some of those mentioned above.
This intermediate article of manufacture would be cylindrically formed at this point in the first stage of assembly. The cylindrical carcass is then expanded into a toroidal shape after completion of the first stage of tire building. Reinforcing belts in the tread are added to this intermediate article during a second stage of tire manufacture, which can occur using the same building drum or work station.
This form of manufacturing a tire from flat components that are then formed toroidially limits the ability of the tire to be produced in a most uniform fashion.
In U.S. Pat. No. 3,935,894, issued Feb. 3, 1976, Jacques Pouilloux indicated that carcass plies could be laid in hoops or arcs having the ends of the carcass cord plies extending in a circumferential direction. It was his objective that a tire made this way could be dispensed of any circular bead core in the beads and the carcass would not have any lateral parts turned up radially with the edges delimited by cut cables. Others have also described constructing the ply using hoops of circular arcs so that the individual ply cords are laid across the convex toroidal cross section in its early stage of manufacture as opposed to being made in the flat construction.
One of the outstanding issues has been how to secure the radially inner end of the carcass cord plies, while also achieving a high force in the lower region of the tire to properly seat and retain the tire upon the wheel rim. The prior art teaches placing the cord ends adjacent vertically oriented and aligned columns of bead wires. The bead wires may be calendered to form a bead sheet.